This may be a silly question...when I fill up I print out the receipt and then write the odometer reading on it. When I update my Fuelly page, I record the gallons pumped and odometer reading at time of fill up. I think I am doing this wrong.
The odometer reading tells me the distance travelled on my previous fill up, right? Should I initially record gallons pumped and update the odometer reading when that tank is empty?
nah, you had it right the first time. Just jot down the odometer reading and enter it when you enter the gallons. The idea is to get a running average by noting the difference from full each time. The distance traveled won't match up with the exact fuel you put in the tank, but we're not doing anything that precise here. This method of tracking is all about starting an easy routine to check your mileage to get a realistic average and note any long term trends.